So the description on this upgrade states that it will: "also applies the disruptor bonus to the front of the ship", but that is where disruptors are already. Is this a typo? Or am I missing something?

Basically this upgrade, on it's own, makes the Tau the best long-range fighters in the game.

Why? Because it applies armor to the shields, meaning enemy Macrobatteries only do ONE QUARTER of their normal damage (One half if they have the AP upgrade).

This means that the Tau will ALWAYS win a long range slugging match unless something changes.

Only Chaos can compete with the Tau on this front, because their Lances ignore armor and have 100% accuracy. Even then though, they only win that due to their +50% damage against shields lance upgrade.